Specific Gravity is a measure of the density of a mineral. It is a useful
property that sometimes becomes the only way to distinguish some
minerals without laboratory or optical techniques.

Specific Gravity is the heaviness
of a substance compared to that of water, and it is expressed
without units. In the metric system specific gravity is the same
as in the English system. If something is 7.85 times as heavy as
an equal volume of water (such as iron is) its specific gravity
is 7.85. Its density is 7.85 grams per cubic centimeter, or 7.85
kilograms per liter, or 7.85 metric tons per cubic meter.

Since the gram was defined as the
mass of a cubic centimeter of water, water must by definition
have a density of 1 gram per cubic centimeter. It actually
varies a little with changes in temperature, but its density is
exactly 1 somewhere around 3 or 4 Celsius degrees above
freezing.

Gold can easily be distinguished from "fool's gold"
by specific gravity alone, although there are many other ways.
Specific gravity is a measure without units, because it is
derived from the density of the mineral divided by the density
of water and thus all units cancel. However, since water's
density equals 1 gram per cubic centimeter (at specific
conditions), then a mineral's specific gravity would also
correspond to a mineral's density as expressed in grams per
cubic centimeter.

Specific
gravity (SG) as already stated compares the density of a mineral
to the density of water. If a mineral has a SG of 2, then it is
twice as dense as water. If a mineral has a SG of 3 then it is
three times as dense as water and so forth. However, comparing a
mineral to water is not practical and is not really helpful. It
is easier to consider what is the SG of a typical mineral and
compare minerals that way.

The
Earth's crust is composed
mostly of the minerals quartz, calcite and feldspar.
These minerals have SG's around 2.75 which is close to the
average SG of the rocks on the outer surface of the Earth's
crust. Therefore, the SG of most rocks that people would pick up
and be familiar with, will have a specific gravity of
approximately 2.75.

To
use specific gravity, hold a mineral of unknown SG in one
hand and in the other hand a mineral of known SG
preferably one near the average of 2.75 and of the same size as
the unknown mineral; then compare". How does the unknown mineral
compare? By convention, comparisons of SG are split between luster
categories: non-metallic and metallic. Non-metallic minerals
tend to be of a low density and we naturally expect them to be
so. So, when one is surprisingly heavy, it becomes very
diagnostic.

Measure
SG

Specific
gravity can be measured accurately by use of sensitive
laboratory equipment. For the average rockhound a good estimate
of SG can be obtained by use of a rigged balance system.

Weigh
the mineral dry. Dry weight = D

Then
weighed the mineral immersed in a liquid, usually water. Wet
weight = W

Now
the SG can be obtained by the following formula:

SG
= D/([D-W]L)

Where
L is the density of the liquid, if water is used, L=1
so
that the formula is simply D/(D-W).

The
mineral being tested must be homogenous and not contain other
minerals. It is best to test single small crystals that are
not attached to a host rock.

Units of
Weight

Units
Of Measure Conversions

Gold Nuggets

For Sale
Notice!

Buyer
Be Ware!

Gold
nuggets being sold online are sometimes sold buy intended
confusing, misleading methods, and, sometimes not real naturally
formed gold nuggets discovered in the Earth!

Advertisers that
do not provide accurate measurements (weight & size) in
certified world standard gold-market trade "troy ounce", and do
not provide images of the
gold nugget along with a size scale in the image, should be
avoided! No Excuses, No Exceptions!

Advertisers that
present their gold nuggets with the weight presented in grns
are to be watched carefully! GRNS is the abbreviation for GRAINS
not grams! This is mostly used to mislead the
average consumer, or is used by an inexperienced person. As a buyer of gold, you
must know how to do the
math and know the units of standard measure for the world gold
market.

Pure Gold
is Bought And Sold By Weight - The World Gold Market Standard Unit
Of Weight Is The "Troy Ounce". When you hear a market
price for gold, that is the price of 1 troy ounce of pure
bullion gold. Make sure you know the troy ounce!

There
Are 480
Grains In 1 ounce (oz.).

A GRAIN is only
.0648 of a GRAM, or .0021 of an ounce.

Example:

Here's an example from an actual auction on
Ebay.

A 43.1
grain
gold nugget, that was manmade, sold for $112! An
Artificially made gold nugget is not that impressive to own, do
to the simple fact anyone can do this! Now Let Us Figure
Out What This Nugget Was Worth AS Just Pure Gold (if it even was
pure gold to begin with).

A)
Do the unit-of-weight conversion math to get the actual gold standard troy ounce
weight:

43.1 grains is 2.8 grams
is .09 of a troy ounce!

B)Calculate the
paid auction price by the price of 1 once of gold.

$112 for .09 of a
troy ounce was paid.

Therefore, 1 ounce divided by
.09 = 11.11.

$112 X 11.11 =
$1,244 USD an ounce (troy ounce)!!!!

C)
Calculate the price paid by the gram.

1 troy ounce = 31grams.

$1,244 divided by 31 grams = $40 a gram.

That's
a lot of
money for a 2.8 gram man-made nugget in my opinion!

A 1
gram nugget is only .032 of an ounce and the size of a match
head. Not very impressive!

Bottom
Line

What Is The Value Of
The Specific Gold Nugget To You?

Some folks just like to collect different types of nuggets as
natural nuggets or to have a One-of-a-kind jewelry piece made of
it. If you like the nugget, and the seller has given you
enough honest information for you to make an informed
decision, and you feel good about the price, then you have invested in a rare piece of what Nature have
created - A One of a kind rare creation!

Gold -
Weight Conversion Chart

Below
is a conversion chart to help
everyone figure out just what they are getting. Following these
self discipline rules may save you from feeling bad about a gold
nugget purchase.

Require the seller to provide
you with the weight and a current picture of the gold
nugget; do not except anything less.

Be careful of whether the ad
is advertising a nugget in grains or grams.

Be careful of the wording used
by the seller to describe the gold nugget; note whether it
is a REAL NATURAL GOLD nugget, (a natural nugget, one dug
from the ground), or a REAL GOLD nugget; a nugget someone
made from real gold. A REAL NATURAL NUGGET, one that is made
by Mother Nature and dug from the ground, is more valuable
as a rare prized possession.

GRAIN
(grn)

GRAM
(g)

DWT
TROY

OZ
TROY

OZ
AV

GRAIN

1.0000

0.0648

0.0417

0.0021

0.0023

GRAM

15.4324

1.0000

0.6430

0.0321

0.0353

DWT
TROY

24.0000

1.5552

1.0000

0.0500

0.0549

OUNCE
TROY

480.0000

31.1035

20.0000

1.0000

1.0971

OUNCE
AV.

437.5000

28.3495

18.2292

0.9115

1.0000

Accuracy:
4 decimal places. oz = ounce. av = average.

DWT

DWT
= Penny Weight. This is a convenient way to size nuggets
in U.S.A. because 20 pennyweights equal 1 troy ounce.

20
pennyweights equal 1 troy ounce.

Example: 5 dwt is
a 1/4 ounce, 10 dwt is a 1/2 ounce etc.

Grams

Grams
seems to be the most widely used weight measurement amongst gold
nugget sellers today. Keep in
mind that there are 31 grams to 1 ounce.

Example: an 8 gram nugget is a
little over a 1/4 ounce, a 16 gram nugget is over a 1/2 ounce.

The Specific
Gravity Test

GOLD

Use the following
method to find the gold content of a gold nugget.

We will use a gold
nugget that is mixed with quartz as a working example to demonstrate
the testing method.